Mark Collier / Staff Photo
Barre police and members of the Washington County Sheriff's Department block off North Main Street in front of North End Deli Mart on Wednesday evening as clean-up crews prepare to drill exploratory holes to determine the extent of a gasoline leak that was discovered Tuesday.

BARRE — State and city officials say they hope to know by week’s end the extent of the area contaminated by a gasoline spill that is being blamed on a mechanical failure at a North Main Street convenience store.

Up to 3,000 gallons of super unleaded gasoline leaked into the ground at North End Deli Mart over an undefined period of time due to a metal flex hose that apparently failed in one of the gasoline pumps.

A city official said the fuel didn’t appear to have made it into the municipal water system or the Stevens Branch of the Winooski River. Health concerns associated with the leak appeared to be minimal, although neighbors have reported gasoline smells in nearby residences over the past three weeks.

During a Wednesday afternoon news conference, David Simendinger, president of Wesco Inc., which owns the convenience store, said the leak was discovered by store employees and reported to state officials Tuesday afternoon — sparking what Deputy Fire Chief Joe Aldsworth said was a multi-agency response.

According to Aldsworth, power to the pumps at North End Deli was cut off Tuesday afternoon and officials for several state agencies, two city departments and a private contractor mobilized at the site Wednesday.

With the leak halted, Aldsworth said test borings are being done to try to identify the outer boundaries of contamination, and that answer should be in hand by Friday.

Armed with that information, Aldsworth said, state officials working with a private contractor will determine how best to mitigate the problem. Some soil, he said, could be excavated or aerated and a collection system could be installed to prevent groundwater from carrying contaminants off site.

Though the extent of the contamination remains unclear, Aldsworth said it doesn’t appear the gasoline had entered the city’s storm sewer system and, by extension, the nearby Stevens Branch. There is no evidence it breached the municipal water system, he added.

However, Aldsworth said some of the spilled fuel has leaked into the city’s sanitary sewer system, probably accounting for petroleum-like odors that have been reported by the occupants of nearly a dozen nearby residential properties over the past three weeks.

The city has responded to each of those complaints — primarily on Second Street and Fortney Place — and tried in vain to find the source of the problem. That search, which involved sewer department personnel, ended early Tuesday afternoon when North End Deli called to report a potential leak due to gasoline that could not be accounted for.

Aldsworth said the leak was confirmed by 2:30 p.m. Gasoline service was immediately and indefinitely suspended, though the convenience store remains open for business.

Christopher Herrick, chief of the Vermont Hazardous Materials Response Team, said no tests at neighboring properties that were done before or after the leak was detected revealed a risk of fire or explosion, and health concerns appeared to be minimal.

“The fire department did not find any reason to evacuate these houses,” he said.

Dr. William Irwin of the state Health Department essentially concurred with that assessment, suggesting that steps already taken to vent the sewer line should prevent the sort of chronic exposure to petroleum fumes that could pose a health risk.

On Wednesday the city removed manhole covers and installed fans to ventilate the sewage system until a contractor could set up a ventilation system. Most of the gasoline in the system was expected to evaporate.

At the invitation of Mayor Thomas Lauzon, both Irwin and Herrick were scheduled to attend a 7 p.m. meeting in council chambers at City Hall to answer questions from any anxious residents.

“I think it’s imperative that people who have questions and concerns have an opportunity to get answers,” Lauzon said, vowing that the city would closely monitor the cleanup efforts.

The leak was at least the third from Wesco in Vermont since 1998, including one last year in Essex.